Arresting hook device for grounded aircraft pilot trainers



Oct. 19, 1948. R. B. BUCHANANl ARRESTING HOOK DEVICE FOR GROUNDED 1AIRCRAFT PILOT TRAINERS` Filed oct. 1 2, 1945 A TTORNEY Patented Oct. 19, 1948 ARRESTING HOOK DEVICE FOR GROUNDED AIRCRAFT PILOT TRAINERS z; Russell B. Buchanan, Lynbrook, Y., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application October 12, 1945, Serial No. 622.067

7 claims. l

This invention relates to an operational ilight trainer and more particularly to circuits and apparatus for simulating the control of the arresting hook of a carrier based airplane.

A carrier based airplane is provided with a retractable Aarresting hook located in the underside of the tail structure near the rear end thereof which may be extended under control` of the pilot when he comes in for a landing on the flight deck of the carrier. The hook when extended and when the pilothas brought the main landlng gear wheels of the airplane into engagement with the ilight deck of the carrier, will engage Aone of several cables which the carrier crew has stretched across the flight deck-and supported a few inches above the flight deck preparatory to receiving airplanes back on the flight deck of the carrier. When the extended arresting hook of an'airplane h ooks onto a cable, the airplane is quickly brought to rest.

lThe arresting hook is, under'normal conditions, either extended or retracted by. an electric motor controlled by a switch located on an electrical distribution panel in the cockpit of the airplane, the motor being operated in one direction lto extend the hook when the control switch is operated to the.out position and being operatedr inthe other direction to retract the hook when theY control switch is operated to the in position. A lamp is associated with the control switch which becomes lighted to inform the pilot when the hook has been fully extended.

In the event that the electric motor control fails, the hook may be extended manually by the operation of -a T-handle arresting hook emergency control which is located adjacent to the pilots seat. To manually extend the hook the pilot pulls the T-handle out to the limit of its movement several times whereby a pawl and ratchet mechanism operated thereby serves to extend the hook. When the hook has been fully extended by the repeated oper-ation of the T- handle, the lamp associated with the electric control switch will light. The arresting hook cannot be retracted by the manual control.

It is the object of the Vpresent invention to simulate in a ground trainer, the operation of the arresting hookunder bothelectric and manual controls and to provide signals atan instructors desk which will indicate to the instructor what steps the pilot is taking to get the hook extended before coming in for a simulated landing.

To enablethe objectV of the invention to be attained, thev trainer isl equipped with an electric v control switch Yand'associated lamp mounted onv an electrical distribution panel of the'cockpit of the trainer in the position which such switch and lamp would occupy in the actual airplane which the trainer is designed to simulate and having the same appearance that they would have in the airplane. Also a T-handle arresting hook emergency control of the same construction and located in the same yposition in the cockpit of the traineras it would have in an actual airplane is provided.

The electric control switch through relays lights lamps at the instructor's desk to inform the instructor whether the pilot h-as operated the switch to its out" or to its in position and one of which relays lights the hook out" lamp associ-ated with thefswitch when such switch has been operated to its out position. The T-handle emergency control in the trainer when pulled out to its fully extent five times against the tension of a loading spring and released, operates a chain of counting relays .which counts the num'- ber of times the handle is pulled out and after the handle has been released, following its fth operation, causes the lighting of the hook out lamp and the locking of the handle .against further operation. Lamps provided at the instructors desk and controlled by the chain of relays inform the instructor that the emergency manual control is being used by the pilot and when the hookvhas been fully extended under such manual control.

For a disclosure ofthe invention,- reierence may be had to the single sheet of drawings.

The "hook out switch and hook out lamp form a unit assembly which is mounted on an electrical distribution panel in the cockpit of the Y trainer.

Also mounted on this panel are the batteryrswitch and a plurality of circuit-breakers which control various circuits of the trainer,

one of which, AH, controls the circuits which are concerned with the simulation of the operation of the arresting hook. Such lamps and keys at lthe instructors desk as are concerned with the vstructors desk.

simulation of the operation of the arresting hook are shown in the dot-dash rectangle labeled In- The relays disclosed in the drawing are all mounted in the apparatus cabivnetsconnected by cables with the Inockup of the airplane fuselage and with the instructors desk.

The T-handle emergency control mechanism is disclosed schematically in the lower portion of the drawing. This mechanism comprises an operating pulley l around the grooved periphery of which a cable .2 is wrapped. One end. of this cable is secured Vto -thepulley 'and the other end is secured to the T-handle 3. The T-handle is slidable through the bulkhead back of the pilots seat and is accessible for operation by the pilot. The pulley I is mounted on a shaft 5 suitably journaled in the two parallelly disposed mounting plates E and 'I of the supporting frame 4. The shaft 5 is rotatable by the pulley I against the restraint of the spiral spring 8 which surrounds the shaft 5 and has one of its ends engaged in a hole in the plate 'I and the other of its ends secured to the collar 9 mounted on and secured to the shaft 5. The spring 8 is tensioned to normally hold the arm I secured to pulley I against the stop stud II and supplies a load to the T-handle. 3 which is equivalent to the load applied thereto in the operation of the ratchet mechanism of an actual airplane which extends the arresting hook.

Positioned below the shaft 5 and slidable in holes provided in the plate 6 and in the bracket I2 is a rod I3. The rod I3 has two collars I4 and I5 secured thereto. Surrounding the rod and positioned between the bracket I2 and the collar I4 is a spiral spring I9 which is tensioned to normally move the rod I3 towards the right in which position the outer face of collar I5 engages against the inner surface of the pl-ate 6. The

other end of the rod I3 is secured to the end of the core I3 of solenoid I'I which is secured to the back plate of the frame 4.

With the coil I8 of the solenoid I'I deenergized and the collar I5 pressed against the plate 6 by the spring I9, the arm I0 is free to move over the rod I3 through the space between the collars I4 and I5 when the pulley I is rotated by the T-handle 3 and attached cable 2, until the pulley I makes nearly a complete revolution or until the arm I8 engages the back of the stop stud I I. The shaft 5 by cams 20 and 2I mounted thereon, controls the operation of the two spring assemblies 22 and 23. The spring assembly 22 is operated to its alternate position by cam 20 except in the normal position of the shaft 5 in which the arm I0 is held against the front of the stop stud II by spring 8,

-and the spring assembly 231s operated into its alternate positionby the cam 2| when the shaft 5 has been rotated through nearly a revolution or when the arm I0 rests against the back of the stud II. v

The apparatus having now been described, the manner in which it functions to train a pilot in the use of the equipment of an airplane which it simulates will now be discussed. To prepare the trainer for use the pilot operates the battery switch to its closed position thereby establishing the circuit of the MB relay 24 which connects battery and ground to battery and ground busu bars 28 and 29 of the trainer and closes the circuit-breakers on the electrical distribution panel in the cockpit of the trainer. Since only the AH or arresting hook circuit-breaker is of interest in connection with the present invention, this circuit-breaker is the only one illustrated in the drawing. The closure of this circuit-breaker es tablishes an obvious circuit from ground, through resistance 25, over the contacts closed by the circuit-breaker and through the winding of the AR circuit-breaker yrelay 25 to battery. As soon as the simulation of the starting of the engine has been completed and the enginefhas attained a simulated speed of 1300 R. P. M., the GEN relay 21 operates in the manner described in the copend- 1 ing 'applicationV of Germanton Serial No. 622,070,

iiled concurrently herewith, andconnects battery 4 and ground to the battery and ground bus-bars 28 and 29.

It will be assumed that in the course of the training flight the pilot is simulating a landing on the ight deck of a carrier and preparatory to landing operates the hook out switch to its left or out position in simulation of controlling the electric motor mechanism of an airplane to extend the arresting hook to its out position and holds the switch in its operated position until the hook out lamp lights. The closure of the switch es tablishes an obvious circuit for the hook out (HO) relay 30 which, over its upper contacts, establishes the circuit for the arresting hook out lamp at the instructors desk to inform the instructor that the pilot is attempting to extend the hook by the electric motor. If this attempt is to be successful the arresting hook key 3I at the instructors desk will be in its normal or closed position and with the circuit-breaker relay 26 operated; repren sentative of the fact that power is available to operate the arresting hook motor, a circuit is estab lished from battery over the contacts of key 3i, over the lower contacts of relay 26, over the inner contacts of relay 30 and in parallel through the hook out lamp on the pilots electrical distribution panel and through the arresting hook lamp at the instructorsdesk to ground. These lamps will then both light to indicate that the hook has been successfully extended.

The instructor may prevent the lighting of these lamps by operating the key 3I whereupon the pilot, not seeing the hook out lamp light, should take steps to control the manual extension of the hook. The instructor may also prevent the lighting of the hook out lamp by simulating the blowing of the circuit-breaker AH through the operation of key 32. The operation of key 32 connects battery directly to the thermal circuitbreaker AH and if the key is held operated for a few seconds the circuit-breaker will blow open and the circuit of relay 26 will then be opened when the key 32 is released. Until the pilot recloses the circuit-breaker AH, lamp 33 associated with the key 32 at the instructors desk remains lighted over a circuit from ground on bus-bar 23, over the back contact of relay 26 and through lamp 33 to battery. When the pilot is successful in causing the hook to be'extended by the motor` and the hook out lamp lights as previously described, the restoration of the hook out switch to its neu tral position releases relay 30 and extinguishes the hook out" lamp and extinguishes'the out and arresting hook lamps at the instructors desk. After landing he maycause' the hook lto be retracted by the motor by operating the hook out switch to its right or in position thereby establishing an obvious circuit for the hook in (HI) relay 34 which upon operating establishes an obvious circuit for the in lamp at the instructors desk. The lighting of the in lamp informs the instructor that the hook out switch has been operated by the pilot to the in position to retract the hook.

Should the hook out lamp fail to light, indicative of the fact that the motor for extending the hook has failed, the pilot then tries to'extend the hook by pulling out and releasing the emergency T-handle 3 ve times. When the handle is pulled Vout to its full extent the first time, the cam 2I operates and locks over a circuit from battery through-its lower winding and lower contacts to ground over the alternate contacts of the spring Y assembly 22. When Athe handle is-thereafter released and the arm `Ill is restored under the iniiuence of the spring 8, the cam 2| permits the spring assembly 23-to restore and open the initial circuit of relay v35, vbut the locking circuit of such relay will remain closed until the arm l engages the stop Il at which time cam 20 will permit the spring assembly 22 to reopen the locking circuit of relay 35.

During the time that relay 35 is operated, an

"obvious circuit is established over its upper contactsfor the EMG lamp at the instructorsv desk to inform the instructor that the pilot has resorted to the use of the emergency equipment land a circuit is established from ground over the upper inner contacts of relay 35, over the upper -back contact of the Z3 relay 36, over conductor 31, over the lower normal contacts of the W relay 38, over the upper back contact of the Z2 relay 39, through the winding of relay 38 and through resistance 40 to battery. A circuit is also closed' from ground applied to conductor 31 by relay 36, over the lower normal contacts ofrelay 38, through the winding of the Z relay 4| and through resistance 42 to battery, but the winding of relay 4| is shunted overits own back contact and relay 4| does not therefore operate. Relay 38, however, operates and locks in a circuit from ground over the normal contacts of V.the LK relay 43,v over the lower alternate contacts of re- 'Alay 38, over the upper back contact of relay 39,

3 a second time, relay 35 again operates and locks and in operating again lights EMG lamp atrthe instructors desk and reconnects ground to'conductor 31. The connectionof ground to conduc.

tor 31 -now establishes -a shunt of the winding of relay 38 over the lower front contact of relay 4|, through the winding of relay 38, over the upper back contact of relay 39, over the lower alternate contacts of relay 38 and to ground at the back contact of relay 43. Relay 3 8 thereupon releases butrelay 4| remains operated over a circuit from ground on conductor 31, over the lower normal contacts of relay 38, through the winding of relay -4| and resistance 42 to battery so long as relay35 remains operated. `With relay 38 released and relay v4| operated, a circuit is established from ground vover the upper contacts of such relays, through the lower normal contacts and winding of the Wl relay 44 and through resistance 45 to battery. A circuit is also established in parallel through the winding of the Z| relay 46and resistance 41 to battery but the winding of relay 46 Vbeing'shunted at this time over its own lower back contact, relay 46 does not operate. Relay 44, however, operates and locks in a circuit from battery through resistance 45, through its winding and over i-ts lower alternate contacts -to ground at the back contact of relay 43. When l relay 35 releases at the end of the releasing move- @ment of the T-handle 3'and removes ground from conductor 31, relay 4| releases and in turn re- -moves ground from the lower back contact of relay 46. Relay 46 now operates in a circuit from battery through resistance 41, through its winding and over the lower alternate contacts of relay 44 to ground at the back contact of relay 43. The .f

the control of relay 43. When relay 35 again releases at the end of the third releasing movement of the T-handle the EMG lamp at the instructors desk is again extinguished and ground is removed from conductor 31 whereupon the ground applied to the lower back contact of relay 4| which has maintained the winding of such relay shunted is removed and relay 4| again operates over a circuit which may be traced from battery through resistance 42,-through its winding and over the lower alternate contacts of relay 38 to ground at 'the back con-tact oi' relay 43.

In response to the pulling out of the T-handle a fourth time, relay 35,/again operates and locks and in operating lights the EMG lamp at the instructors desk and reconnects ground to conductor 31 whereupon, with relay 4| now operated, the previously traced circuit is effective for shunting down' relay 38. i Relay 38 upon releasing establishes the previously traced holding circuit for relay 4| over its lower normal contacts so that relay 4| will now remain operated so long as relay 35 remains operated. With relay 4| operated and ground over the upper contacts of relays 38 and relay-38 now released, a circuit is established from '4| over the lower front contact of relay 46 and to the junction point between resistance 45 and the winding of relay 44 thereby shunting down relay 44. Relay 45 is now held operated in a locking circuit from battery through resistance 41, through the winding of relay 46, over the lower normal contacts of relay 44 and the upper contacts of relays 4| and 38 to ground so long as relay 4| remains operated. With relay 46 operated and relay 44 now released, a circuit is established from ground over the inner upper contacts of relay 35, over the upper back contact of relay 44,

-over the upper front contact of relay 46 and through the lower winding of the Z2 relay 39 to battery, whereupon relay 39 operates and locks from battery through its upper winding and over its upper front contact to ground at the back contact of relay 43. y

Whenrelayi35 again releases at the end of the fourth releasing movement of the T-handle, the EMG lamp at the instructors desk is again extinguished and ground is removed from conductor 31 whereupon with relay 38 released, the locking circuit of relay 4| is opened and relay 4| releases. With relays 38 and 4| now both released, the locking circuit of relay 4'6 is opened and relay 46 releases.

InV response to the pulling out ofthe T-handle for the fth time, relay 35again operates and locks and in operating lights the EMG lamp at the instructors desk and establishes a circuit from ground Voverits inner upper contacts, over the upper back contacts of relays 44 and 46, over thelo-wer contacts of relay 39 and through the inner lower normal contacts and winding of the Z3 relay 3`to battery. Relay 33 thereupon opcrates and locks over its inner lower alternate contacts to ground at the back contact of relay 43. With relay 39 operated, the reoperation of relay 35 is ineffective to further control the operation of relays 38 and lll. At its upper contacts, relay 3E connects battery to the circuits of the hook out lamp on the pilots distribution panel and the arresting hook lamp at the instructors desk indicative of the fact that the hook has been manually extended.

When the T-handle is again released and the cam 2U reaches its normal position, a circuit is established from ground over the spring assembly 22 in its normal position, over the lower contacts of relay 36 and through the winding I8 of the solenoid Il to the ll5volt source of power. The solenoid nowattracts its core and thereby moves the collar i5 into the path of arm l0. Should the pilot again try to pull out the T-handle it will resist such movement since the arm I0 is now blocked. This simulates the blocking of the T- handle when the ratchet mechanism operated thereby in a regular airplane has extended the arresting hook to the limit of its movement.

To restore the operated relays 33 and 39, the instructor may operate the switch 48 thereby operating the locking ground supply (LK) relay 43 which removes locking ground from relays 3B and 39. When relay 33 releases, the hook out and arresting hook lamps become extinguished and the solenoid I1 is released.

What is claimed is:

l. In apparatus for simulating the operations? incident to the extension of the arresting hook of a carrier based airplane, a switch operable by a'pilot under training to either an out or to an in position in simulation of the electrical control of the arresting hook of an airplane, an kinstruc-,fgao

tors desk, a lamp associated with said switch and a lamp at said desk, a circuit established when said switch is operated to its out position for lighting said lamps, and a key at said instructors desk for rendering said circuit ineiective to simulate the failure of the electrical control of the arresting hook.

2. In apparatus lor simulating the operations incident to the extension of the arresting hook of a carrier based airplane, a switch operable by a pilot under training to either an out or to an in position in simulation of the electrical control of the arresting hook of an airplane, an instructors de-sk, a lamp associated with said switchand a lamp at said desk, a circuit-breaker, a circuit established if said circuit-breaker is closed and said switch is operated to its out position for lighting said lamps, and a key at said instructors desk for causing said circuit-breaker to open to render said circuit ineffective in simulation of the failure of the power supply for the electrical control oi the arresting hook.

3. In apparatus for simulating the operations incident to the extension of the arresting hook of a carrier based airplane, a switch operable by a pilot under training to either an out or to an in position in simulation of the `electrical control of the arresting hook of an airplane, an instruckus tors desk, a lamp associated with said switch and a lamp at said desk, a circuit established when said switch is operated to its out position for lighting said lamps, a key at said instructors desk for rendering said circuit inelective to simulate the failure of the electrical control of the arresting hook, an emergency control handle operable fby the pilot should the electrical control fail, a

switch operable in response to the operation of said handle to the limit of its movement, counting relays successively operated in response to the repeated operation of said switch when said handle is repeatedly operated, and a circuit controlled by said relays for causing said lamps to light when said handle has been operated the number of times which would be requisite to cause the full extension of the arresting hook of an actual airplane.

4. In apparatus for simulating the operations incident to the extension of the arresting hook ofV a carrier based airplane, an emergency control handle, a switch operable in response to the operation of said handle to the limit of its Inove-` ment, counting relays successively operable in response to the repeated operation of said switch when said handle is repeatedly operated, a lamp, a circuit controlled by said relays for causing said lamp to light when said handle has been operated the number of times which would be requisite to cause the full extension of the arresting hook of an actual airplane, and means controlled by said relays for locking said handle against operation after said handle has been operated said requisite number of times.

5. In apparatus for simulating the operations incident to the extension of the arresting hook of a carrier based airplane, an emergency control handle, a switch operable in response to the operation of said handle to the limit of its movement, a control relay operable upon each operation of said switch, an instructors desk, a lamp at said desk lighted upon each operation of said relay to inform the instructor that the pilot under training is using the emergency handle, counting relays successively operable in response to the repeated operation of said control relay upon the repeated operation of said control handle, a hook out lamp observable by the pilot under training, a hook out lamp at said instructors desk, and a circuit controlled by said counting relays for causing said latter lamps to light Vwhen saidhandle has been operated the number of times which would be requisite to cause the full extension of the arresting hook of an actual airplane.

6. In apparatus for simulating the operations incident to the extension of the arresting hook vof a carrier based airplane, an emergency con- -trol handle, a shaft, a pulley secured to said shaft and yrotatable through substantially one revolution in response to each operation of said handle to the limit of its movement, a loading spring for restraining the movement of said shaft, a switch operable by a cam on said shaft, counting relay-s successively operable in response tothe repeated operation of said switch whensaid handle is repeatedly operated, a lamp, a circuit controlled by said relays for causing said lamp to light when said handle has been oper- A ated the number of times which would be requiyof a carrier based airplane, an emergency control handle, a shaft, a pulley secured to said shaft and rotatable through substantially one revolutioninresponse to each operation of said 9 handle to the limit of its movement, a loading spring for restraining the movement of said shaft, a first switch operable by said shaft when said handle is operated to the limit of its movement, a control relay operable by said switch, a transfer switch operable to its alternate position whenever said shaft is operated out of its normal position, a locking circuit for said relay controlled by said latter switch whereby said relay when operated is held operated until said handle returns to its normal position, counting relays successively operated in response to the repeated operation of said control relay upon the repeated operation of said control handle, a lamp and a circuit jointly controlled by said relays and by said latter switch for causing said lamp to light when said handle has been operated the number of times which would be requisite to cause the full extension of the arresting hook of an actual airplane. l

RUSSELL B. BUCHANAN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

